The invention relates to a device and a system suitable for cutting a pipe, for example a liner installed inside a sewage pipe, and to use thereof for cutting a pipe from inside the pipe.
In prior art solutions, inner surfaces of sewage pipes have been machined from inside the pipe by means of grinding robots, for example. The robot may have a spherical blade attached to the end of an arm, for example, which blade, while rotating, grinds the inner wall of the pipe and can be controlled by appropriate control devices. The grinding blade is operated by a pneumatic motor, for instance. Due to the low torque generated by pneumatic operation, the speed of rotation required for the grinding blade may be very high, for example 10 000 to 30 000 rpm. The robot is pushed to the cutting point inside the pipe by means of rigid push bars.
A problem with prior art solutions is that the machining is slow and susceptible to errors. For instance, an incorrect control command to the robot may damage not only the pipe to be machined but also another pipe that surrounds the pipe to be machined. Further, it is often difficult to move the grinding robot inside a sewage pipe, possibly through a plurality of sharp turns, to the desired location. Proceeding through turns is not always successful, so the grinding robot must often be operated from the pipe end different from the one through which the coating was applied, in which case it may be necessary, for instance, to open the gully hole in the street and close the street to traffic for the duration of machining.